What is the key characteristic that defines the Ecdysozoa clade?

What is the key characteristic that defines the Ecdysozoa clade?
  a. The animal molts.
  b. The animal is a deuterostome.
  c. The animal has motile larvae.
  d. The animal has bilateral symmetry.
  e. The animal develops three tissue layers.

Question 2

Determinate cleavage takes place in ____ and is characterized by a pattern of development where the ultimate fate of
  each cell is ____.
  a. deuterostomes; not fixed until late in the developmental process
  b. protostomes; not fixed until late in the developmental process
  c. deuterostomes; fixed early in the developmental process
  d. protostomes; fixed early in the developmental process
  e. coelomates; fixed early in the developmental process